The chum salmon, Oncorhynchus keta Walbaum, spawning in rivers and lakes of the Far East, is divided into ecogeographic units (EGUs) based on zoogeographic zoning of the species range, biological features of groups that take into account spawning areas and ecological forms (ecotypes), and genetic differences between them. Each EGU has definite geographical boundaries and can include several spawning populations of chum salmon from different water bodies within these boundaries. Populations of chum salmon from different EGUs have significant genetic differences between each other. Ecogeographic units are important elements of the intraspecific structure. They can also be considered as basic management units of chum salmon, which should be taken into account when developing a strategy for managing stocks of aquatic biological resources. In particular, in the process of artificial reproduction of this species, transfer of fertilized eggs between populations from different EGUs is highly undesirable.

Six ecogeographic units are verified in chum salmon Oncorhynchus keta (Walbaum, 1792) that spawns in the rivers of Iturup and Kunashir islands based on the zoogeographical zoning: of the physical-geographical regions of their spawning, certain ecological forms (ecotypes), and genetic differences between them. These are lake chum salmon of Lake Sopochnoe, river chum salmon from the basins of the Reidovaya and Kurilka rivers (Iturup Island), and river and lake forms of chum salmon of the Kunashir Island. The river chum salmon of Rybatskaya River (Iturup Island), eligible for protection due to its genetic uniqueness, is defined as a special (sixth) ecogeographic unit. These ecogeographic units are finally verified via assessment of their differentiation on the basis of DNA markers. In addition, the chum salmon of the Kuibyshevka River basin, water bodies north of Vetrovoe Isthmus, and those in the southern portion of the island should possibly be classified as additional ecogeographic units; however, their genetic features are understudied, which hinders their reliable verification. All listed ecogeographic units as a whole can be viewed as basic management units for the chum salmon of the southern Kuril Islands. The lake ecotype of Kuril Islands is liable for protection and careful approach to fishery and reproduction as a unique form of chum salmon of the Far East.

The review is devoted to the current state of research on salmonid fishes in natural populations and aquaculture, performed using high-throughput transcriptomics technologies. The studies describing the molecular basis of fish growth and development, as well as studies on genetic variation underlying the ecological and evolutionary adaptations of the genus Oncorhynchus, are evaluated. Systemic changes in small, long, and circular noncoding RNAs profiles that occur in fish transcriptomes in response to different effects are characterized. The identified signaling cascades, which play key roles in the development of economically valuable traits, can be used as targets for selective fish breeding within the framework of targeted commercial traits.

Льву Анатольевичу Животовскому, профессору, доктору биологических наук, выдающемуся учёному, внёсшему большой вклад в популяционную и эволюционную генетику, заведующему лабораторией генетических проблем идентификации Института общей генетики им. Н.И. Вавилова РАН, главному научному сотруднику Отдела молекулярной генетики ВНИРО, лауреату Государственной премии в области науки и техники РФ, заслуженному деятелю науки РФ, лауреату премии в области эволюционной биологии имени И.И. Шмальгаузена РАН 22 ноября исполнилось 80 лет.

Using the example of chum salmon Oncorhynchus keta in the Amur zoogeographic province, we review the principle of subdividing the species into population groups. On the basis of zoogeographic zoning and biological boundaries of chum salmon groups defined by the spawning areas, taking into account the distribution, migration, and reproduction, as well as estimates of their differentiation using microsatellite DNA markers, we identified eight ecogeographic units in the Amur province. In the Amur zoogeographic region of this province, these included the summer chum salmon of the Amur-Amgun ecoregion and the autumn chum salmon of the Lower Amur (Amur-Amgun and Amur-Ussuri ecoregions); in the Shantar zoogeographic region of the province, the Uda-Tugur and Ulban groups; in the Sakhalin part of the Amur province, groups from the northwestern and northeastern Sakhalin, as well as summer and autumn chum salmon from the Poronai River. These ecogeographic units can be considered as basic spawning management units of chum salmon for this part of the species distribution range.

A panel of 15 microsatellite loci was used to study the modern structure of the sable gene pool in the southern part of the range. A high level of population differentiation was determined. The existence of several population clusters of the sable was revealed on the vast territory from Western Siberia to Transbaikalia. This part of the species range is distinguished by a high number of sables; another peculiarity is that the territories allowed for hunting alternate with a significant number of reserve territories. The abilities to identify individuals by population and regional affiliations were determined. In the study, the reliability of the prediction of population belonging (SCOR coefficient) of individuals to the pooled sample was estimated; the estimate showed that the accuracy (the number of correctly identified individuals) and reliability of identification significantly increases on average for each individual with an increase in the number of loci from 8 to 15. The results of the study complement the reference database of genetic data of populations of geographic regions of the species and make it possible to solve a number of problems associated with hunting on the territories bordering the nature reserves, which contributes to the preservation of intraspecific diversity of the sable.

The study includes 41 sample sets of chum salmon from the northern part of its geographic range analyzed at ten microsatellite loci. In the northern part of the range of Asian chum salmon, the following groups of samples are clearly distinguished: “Magadan oblast,” “Northern Kamchatka,” “Penzhina River,” and “Anadyr River basin.” Populations of chum salmon from the Apuka River and the “Koryak Upland” group show low genetic differentiation from other groups. There is a positive relationship between the latitude and the average expected heterozygosity in this part of the range. Chum salmon of the Penzhina River shows close genetic relationship to chum salmon from the Anadyr River basin, probably because of gene flow.

The genetic structure and differentiation level of the sable populations from the Altai mountain region and adjacent geographical regions were studied using nuclear and mitochondrial genome markers. The isolation of the sable from northwestern physicogeographical province of the Altai mountain region was confirmed. Previously, the taxonomic status of the sable from this region was determined according to morphological traits as the Martes zibellina averini Bashanov, 1943 subspecies. The results of the statistical analysis indicate the existence of two population groups in the Altai mountain region: northwestern (isolated by landscape peculiarities of the mountain region) and generated by the populations of the east and northeast of the Altai Mountains. The latter have sustainable migration links with the main area of sable of the Altai–Sayan Ecoregion and Central Siberian Plateau. The allelic diversity center of the studied part of the species area was detected.

We study 117 Pacific walrus samples from three rookeries within the western part of Chukchi Sea (Cape Vankarem, Cape Serdtse-Kamen, and Kolyuchin Island). We analyze the variability of nuclear (20 microsatellite loci) and mitochondrial DNA (three fragments). Two microsatellite loci which are described as microsatellites for the first time are used in this study: repeated sequences within introns of Coro1c and Plod2 genes. A high degree of genetic diversity is demonstrated for both nuclear and mitochondrial markers compared to Atlantic walrus. A high degree of genetic diversity is preserved within populations of Pacific walrus, despite a strong decline in the recent past. We discover the absence of significant differentiation for microsatellite loci and the presence of weak differentiation for mtDNA (mainly for a D-loop fragment). Walrus specimens that use the rookeries of the western part of Chukchi Sea are thought to belong to a single reproductive group.

The chum salmon of the Amur River (the mainland part of the Far East) and the Poronai River (Terpeniya Bay, Sakhalin Island) are historically related to one another, as the drainage basins of these rivers are the remnants of a formerly single river system, the Paleoamur, which existed when Sakhalin Island was a part of the continent. Both river populations of chum salmon consist of the early-run and late-run ecological forms (seasonal races), which are also referred to as the summer and autumn races. They are reproductively isolated from each other due to their spawning at different times and in different types of spawning grounds. To assess the direction, pattern, and degree of divergence between these chum salmon races in the both river fragments since the Paleoamur, it is necessary to compare them using two types of traits: selectively neutral DNA markers and morphological and physiological traits, variations in which may have an adaptive value. For this, we have studied chum salmon from both rivers in terms of microsatellite DNA markers, body counts and measurements, body weight, and fecundity. Both in the Amur River and in the Poronai River, the autumn race of chum salmon prevails over the summer race in body length and weight, fecundity, number of pyloric caeca, and several other meristic traits. The intra-basin differences between the races are much more pronounced in the Amur chum salmon. The inter-race differences in microsatellites are also greater in the Amur chum salmon compared to the Poronai chum salmon. Using microsatellites, three levels of differentiation have been revealed: (1) between the basins of the Amur and Poronai rivers, (2) between the races within each of the river basins, (3) and between population samples within each race of each basin. A hypothesis is proposed that the currently existing races of chum salmon in the Amur and Poronai rivers have evolved since the breakup of the Paleoamur, and the intra-basin divergence of the races started in the Amur River earlier than in the Poronai River. An analysis of our own data and the published data suggests that the adaptation of the seasonal races of chum salmon to the conditions of their spawning grounds is determined by a complex of morphological and physiological traits, including the number of pyloric caeca, which is an adaptive and highly heritable trait associated with the incubation temperature of the water.

In this study, 12 samples of chum salmon from the southern and central parts of Primorye were studied with ten microsatellite loci. All studied localities of chum salmon of Primorye formed three main genetically different groups: (1) the Narva–Barabashevka–Ryazanovka cluster of southern Primorye, (2) Kievka River, and (3) Avvakumovka River. The revealed genetic heterogeneity of chum salmon showed clear population structure in accordance with the geographical location of the samples. The study suggests that, for the purposes of artificial reproduction of chum salmon, it is desirable to perform egg planting with regard to the described population structure of chum salmon of Primorye.

A survey of 65 populations of chum salmon Oncorhynchus keta across the species range revealed homozygote excess (947 homozygotes in 2954 fish) at a polymerase chain reaction (PCR)-based simple sequence repeat (SSR) locus oke3 with multiple alleles, whereas re-designed PCR primers indicated that 328 of these homozygotes were actually heterozygotes. Statistically significant high positive values of inbreeding coefficients, f, in multiple populations appeared to be a reliable predictor of null alleles. Based on these data, three methods were checked for their ability to estimate null-allele frequencies.